1. Field of the Invention
The present invention relates to an organically modified layered clay as well as an organic polymer composition containing the same and a tire inner liner formed from the organic polymer composition. More specifically, it relates to an organic polymer composition having layered clay, of which layers are exfoliated, finely dispersed therein, obtained by mixing a certain specific organically modified layered clay with a specific organic polymer. Such an organic polymer composition is suitably used, for example, for a tread, carcass, inner liner, etc. of a pneumatic tire utilizing its abrasion resistance, air barrier property, and other properties.
2. Description of the Related Art
JP-B-6-84456 reports a rubber composition comprising a rubber and layers of a layered clay dispersed therein, while JP-A-8-510421 reports the improvement in the gas barrier property of this rubber composition. Further, JP-A-10-81785 reports kneading an organically modified clay and rubber using a rubber process oil to uniformly disperse the clay in the rubber. Further, JP-A-2000-169634 reports the improvements of the physical properties of an organically modified clay-resin composite material, by using a thermoplastic resin having a polar group such as an acid anhydride group, epoxy group and carboxyl group. However, these polar groups do not react with the organic moiety of the organically modified clay. Further, while allusion is made to the dispersion properties of the clay, it is not clear whether this is a simple dispersion or a dispersion at nanolevel.
Further, according to JP-B-6-84456, an organic solvent should be used during the production of the liquid rubber composite containing a layered clay and, therefore, this is environmentally unpreferable. In addition, in JP-B-6-84456, the liquid rubber composite is prepared by directly reacting a layered clay and a liquid rubber having positively charged group in the main chain or side chain. However, it is pointed out therein that the preparation of the liquid rubber composite having a positively charged group is difficult and that the desired smelling between the layers of the clay is not sufficient by the reaction of the liquid rubber and the layered clay (see column [0003], lines 22-31 of JP-A-9-87432).
Further, JP-A-2002-88208 reports that, by using a halogenated butyl rubber containing a layered clay for the inner liner of a tire, the air barrier property can be enhanced. However, in general the use of a simple layered clay for decreasing the air permeability causes the problem that it is necessary to add a large amount of the layered clay.